Big Flood/Mud Issues Tonight

December 8, 2015

11:45pm Tuesday…

Things went crazy the past two hours in the newsroom with widespread reports of flooding/mudslides/landslides blocking freeways and going into towns.

To summarize:

  • Tons of flooding in Kalama and Rainier this evening.  Almost 4″ of rain in the past 24 hours in those locations as the heavy band of rain sat up there most of today
  • Nehalem River in Vernonia is at its highest level since the big 2007 flood
  • Wilson River at Tillamook and Nehalem at Nehalem the highest since 2007 flood
  • Numerous highways blocked by debris/mud/water to the north and west of the metro area.

Hopefully we can avoid a big deadly mudslide, but I sure wouldn’t be surprised to see lots more slides in the next 24 hours.

Note the big rain totals around the notoriously wet south Washington Cascades.  Over a foot of rain the past 3 days near Ape Cave!

MarkRain_MtHood_Totals


Heavy Rain Returns Tonight

December 8, 2015

There is some good news and some bad news this evening.  The bad news is that heavy rain is moving back into the metro area this hour after a break for several hours.  The good news is that the heavy stuff should be done not too long after midnight.  I expect another 1.0 to 1.5″ at most.

Here’s where we are at PDX as of 9pm:

BMAC Rain Two Day Total

I don’t have the time to take a look at the past 10-20 years, but  I also don’t remember many instances in which we’ve seen almost 5 inches of rain in 3 days.

PLOT_Rain_NWOregon_Autoplot
A discerning weather geek may notice PDX and Vancouver stick out with much higher rain totals today?  That’s because around 1pm a heavy line of showers sat right over PDX and Pearson Airpark.  .53″ in one hour at PDX!  That’s a juicy subtropical airmass for sure, which reminds me that we had another record high today.

BMAC December Heat

I think the biggest problem the rest of the week will be mudslides and landslides.  Soils are totally saturated and additional rain will only exacerbate the situation.

MarkHeadlines_FloodPortland

Chief Meteorologist Mark Nelsen


We’ve Been Cheated! No Tied Record Yesterday

December 8, 2015

The NWS has made a change to that big 2.69″ rain total from yesterday.  They decided to go by calendar day instead of the hourly observations.  That means we have to take .07″ off Monday’s rain total.  Their corrected statement is great (highlights are mine):

Capture

The deal is that observations have never been taken at the top of the hour at official stations.  It has always been a few minutes before the top of the hour.  When we say “it’s 103 degrees right now at 5pm”, that means the observation was 103 degrees at 4:53pm for example.  Been that way my entire career and I assume a long time previous to that.  As far as I’m aware, those have always been counted as “top of the hour” for stats.  But maybe not and we typically don’t notice unless there is a heavy rain event right near the top of midnight?  Can anyone from NWS comment on it?

This just means we were not tied yesterday for wettest calendar day ever…it’s #2 now.

The great shame, knowing I was .02″ off all evening long…

Chief Meteorologist Mark Nelsen